Salts of aromatic dithiocarboxylic acids as fungicides



Patented Jan. 10, 1950 SALTS oF- AROMATIC mgrmoonnnoxyuo I ACIDS AS rUNg o nnsf Pliilip' T. "real, Naugatlick, and Joseph Bjorn n ted ates Rub nmp ms New York.

N. a corporation of New Jersey No Drawinjg. Applioationlloyember 1 1 944, 7

' Serial: No5611492 Thisfinvention relates to new and provements in fungicides.

useful nk The invention further relates to methods of protecting organic ma- 6 Claims. (Cl. 1 67 30) with the various concentrations of different salts of aromatic dithio acids are shown in the following table:

Chemical Blight Lesions per Plant 2000 P. P. M. P. P. M. P. P. M. P. P. M.

Zinc-2-hydroxy-l-dithionaphthoate. 6 36 52 92 Lead-2-hydroxy-l-dithionaphthoate 17 32 49 151 Disodium-2-hydroxy-l-dithionaphthoate. 23 23 164 179 Basic cupric-2-hydroxy-l-dlthionaphthoate 28 126 168 225 Basic ferric-QFlJydroXy-l-dithionaphthoate 49 77 81 122 Cupric-2-hydroxy-l-dithionaphthoate 55 141 179 217 Ferric-2-hydroxy-l-dithionaphthoate 61 135 146 294 Zinc dithiobenzoate 92 94 118 317 Lead ditbiobenzoate 95 126 235 291 terial subject to attack by microorganisms, as in the control of fungi on plants.

We have found that salts of aromatic dithio acids are effective fungicides. Salts of aromatic dithio acids and their preparation are known. For example, sodium dithiobenzoate may be prepared by the action of sodium sulfide on benzotrichloride. Another method of preparation of aromatic dithio acids involves the action of carbon disulfide on a Grignard reagent. Salts of Z-hydroxy-l-dithionaphthoic acid and their preparation are disclosed in U. S. patent to Hardman No. 2,289,649.

The salts of aromatic dithio acids may be used as seed protectants and to protect plants, which term includes plant parts, or soil from microorganisms harmful to seeds and plants. They may be applied as dusts, undiluted or mixed with a solid carrier, such as clay or talc, or as a spray in a liquid carrier, as in solution in a suitable solvent, or suspended in a suitable non-solvent, for example, water. They may be admixed with carriers that are active of themselves, for example, other fungicides or bactericides, insecticides, insectifuges, fertilizers, hormones, buffering or softening agents.

Th following examples are given to illustrate the invention:

45 LB 50 Values Example I Chemical Aqueous suspensions containing 2000, 500, 125 Alternaria Sclerotinia I and 32 parts per million (P. P. M.) of water of various salts of aromatic dithio acids were P PM P P. M.

L cl-2-h dr 11' sprayed onto tomato plants and allowed to dry. 55.. g iiififiii gfigfimii 3'3 81% The thus treated plants and some untreated g i sg gfil n'l gi gryo'iilflilfifiiighthlilgg.i. g g

1 a (check) were then noculated with a spore sus- Ba i ;f j 2. d y dithi ig hth 3 3 pens1on of Alternarza sola'nz, the causal organism ggg f g sgg gg -g b gg ig gggggge of the early blight disease of tomato. Sixty Cupri 2 hydroxy 6 sulfo.i dithion phtho. hours later a count was made of the number of 55 Lead-(iit-fii-fih-zbgtg 8 2g lesions which had developed on the plants. The Zinc dithiobemoate 20 check plants averaged 401 lesions per plant. The QuPric-4-PhenY1-dithi0benmte- 20 0 average number blight lesions per plant treated Theabove shows the effectiveness of salts of aromatic dithio acids as plant fungicides.

Example II Slide tests were made with various salts of aromatic dithio acids on the fungi Alternarza solam' and Sclerotima amerzcana according to the procedure outlined in Phytopathology. Vol. 33, page 627 (1943). In these tests, aqueous suspensions of various concentrations of the diiferent chemicals are mixed with a suspension of the particular fungus spores under observation and drops of the mixture are placed on glass slides to germinate. Observations are made after 20 hours to determine in each case the percentage kill of the spores. From doseage-response curves based on such observations, the concentration of chemical in parts per million of water, that is required to kill or inhibit the germination of of the spores may be determined. This is called the LD 50 value (lethal doses for 50% effectiveness). The LD 50 values for various salts of aryl dithio acids in slide tests on Alternaria solam' and Sclerotim'a americana are shown in the following table:

2. A fungicidal preparation comprising a, powdered solid carrier and a salt of dithiobenzoic' acid. 3. A fungicidal preparation comprising a powdered solid carrier and a salt of 2-hydro r y-l dithionaphthoic acid.

4. A fungicidal preparation comprising a powdered solid carrier and zinc-2-hydroxy-1-dithionaphthoate.

5. A fungicidal preparation comprising a powdered solid carrier and Iead-Z-hydroxy-l-dithionaphthoate.

6. A fungicidal preparation comprising a powdered solid carrier and lead dithiobenzoate.

PHILIP T. PAUL. JOSEPH BJORN SKAPTASON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,648,259 Cadwell Nov. 8, 1927 2,289,649 Hardman July 14, 1942 2,317,765 Hester Apr. 27, 1943 15 2,352,079 Coleman et a1 June 20, 1944 OTHER REFERENCES Jour. Economic Entomology, vol. 27 (1934), pages 1178, 1180, 1181, 1182 by Campbell et a1. 

1. A FUNGICIDAL PREPARATION COMPRISING A POWDERED SOLID CARRIER AND A SALT OF AN AROMATIC DITHIOCARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF 1-DITHIONAPHTHOIC ACIDS AND DITHIOBENZOIC ACIDS. 